Acrylic-based polymer waterproofing material - Methods of the test, Part 4: Determination of Minimum Film Forming Temperature and White Point

IS 13435 Part 5: Scope Overview

IS 13435 Part 5 (1992) deals with design and construction of reinforced concrete chimneys. The scope typically includes:

• Design criteria for reinforced concrete chimneys of various heights.
• Structural analysis under wind, seismic, and thermal loads.
• Material specifications for concrete and reinforcement.
• Construction and quality control guidelines.

Key Specifications (Generalized):

Important Formulas:

• Wind Pressure:
  [ p = 0.6 \times V^2 \quad \text{(kN/m}^2\text{)} ]
  where (V) = basic wind speed (m/s) from IS 875 Part 3.

• Moment due to Wind:
  [ M = p \times A \times h_{eff} ]
  where (A) = projected area, (h_{eff}) = effective height.

• Seismic Base Shear (IS 1893):
  [ V_b = \frac{Z I S_a}{2 R g} W ]

Summary:

• The scope defines design limits, load considerations, and material specs.
• Refer IS 13435 Part 5 for detailed load combinations and construction practices.

flowchart LR
    A[Start: Chimney Design] --> B[Determine Height & Diameter]
    B --> C[Select Material Grades]
    C --> D[Calculate Loads: Wind, Seismic, Thermal]
    D --> E[Structural Analysis & Moment Calculation]
    E --> F[Design Reinforcement]
    F --> G[Construction & Quality Control]
    G --> H[Final Inspection & Approval]

For detailed tables and clauses, consult the full IS 13435 Part 5 document.

IS 13435 Part 5 — Definitions & Key Specifications

Key Definitions (Clause 2.1)

• Minimum Film Forming Temperature (MFT): The lowest temperature at which a continuous, homogeneous film forms without defects.
• White Point (WP): The temperature where the dispersion starts to whiten or become opaque.

Important Table (Clause 5.2.8)

Reporting Requirements (Clause 6)

Test reports must include:

• Identification of dispersion
• Type of testing apparatus
• White point temperature (°C)
• Minimum film forming temperature (°C)

Summary Formula/Concept:

• MFT is determined by gradually cooling a film and noting the temperature at which a continuous film forms.
• WP is identified by observing the temperature at which the dispersion changes visually.

flowchart LR
    A[Dispersion Sample] --> B[Heat/Cool Cycle]
    B --> C{Temperature}
    C -->|Above MFT| D[Continuous Film Forms]
    C -->|Below MFT| E[Film Defects]
    C -->|At WP| F[Dispersion Turns White]

Note: This part of IS 13435 focuses on definitions and test reporting for acrylic-based polymer waterproofing materials. For detailed test methods, refer to other parts of IS 13435.

IS 13435 Part 5: Principle of the Method

This part deals with determining Minimum Film Thickness (MFT) and Water Permeability (WP) of protective coatings.

Key Concepts:

• MFT (Minimum Film Thickness): The thinnest dry film layer required to provide effective protection.
• WP (Water Permeability): Measure of water penetration through the coating.

Key Formula for MFT:

[ \text{MFT} = \frac{W_d}{A \times \rho} ] Where:

• ( W_d ) = weight of dry film (g)
• ( A ) = coated area (cm²)
• ( \rho ) = density of dry film (g/cm³)

Typical Table for MFT and WP (Indicative):

Notes:

• Solid content determination (Part 1) affects MFT calculation.
• Capillary water uptake (Part 3) relates to WP.
• Clause 5.2 details procedures to measure MFT and WP experimentally.

flowchart LR
    A[Coating Sample] --> B[Measure Dry Weight (W_d)]
    B --> C[Calculate MFT]
    A --> D[Water Exposure Test]
    D --> E[Measure Water Uptake (WP)]

This method ensures coatings meet protective performance criteria by controlling film thickness and permeability.

IS 13435 Part 5 - Test Apparatus Key Details

1. Test Apparatus (Clause 4.1.1 & Fig. 1)

• Rectangular plate made of aluminium, stainless steel, or copper.
• Surface options:
  • Perfectly level and polished.
  • Channeled surface: channels 0.3 mm deep and 20 mm wide (optional).
• Holes for thermometers: diameter 0.5 mm.
• Components include:
  • Electrical resistance heater.
  • Reservoir for refrigerant mixture.
  • Dry air inlet.
  • Insulating material.

2. Temperature Measurement (Clause 5.1.1)

• Temperature devices (thermometers) must be installed in designated holes before testing.

3. Minimum Film Forming Temperature (MFT) & White Point (Clause 5.2.8)

• MFT: Lowest temperature at which a continuous homogeneous film forms.
• Report MFT and white point temperatures to the nearest degree Celsius.

4. Reporting Requirements (Clause 6)

• Dispersion identification.
• Type of test apparatus.
• White point temperature (°C).
• Minimum film forming temperature (°C).

Summary Table: Test Plate Dimensions

flowchart LR
  A[Rectangular Plate] --> B{Surface Type}
  B --> C[Polished, Level]
  B --> D[Channeled (0.3 mm deep, 20 mm wide)]
  A --> E[Holes for Thermometers (0.5 mm dia)]
  A --> F[Electrical Resistance Heater]
  A --> G[Reservoir for Refrigerant]
  A --> H[Dry Air Inlet]
  A --> I[Insulating Material]

This setup ensures controlled temperature measurement for determining MFT and white point per IS 13435 Part 5:1992.

IS 13435 Part 5: Coating Bench Key Points

1. Coating Bench Setup (Clause 4.1)

• Used for determining Minimum Film Forming Temperature (MFT) and White Point (WP).
• Film spreader applied on a level plate or channeled plate (see FIG. 2 in IS 13435 Part 5).

2. Film Spreader Specifications (Clause 5.2.1)

• Dry coat thickness: 0.10 to 0.15 mm.
• Coat width: 20 mm.
• Spread starting from the highest temperature end on the plate.

3. Key Definitions (Clause 5.2.8)

4. Reporting Requirements (Clause 6)

• Dispersion identification.
• Testing apparatus type.
• White Point temperature (°C).
• Minimum Film Forming Temperature (°C).

Summary Table: Film Spreader Parameters

flowchart LR
    A[Prepare Level Plate] --> B[Apply Film Spreader]
    B --> C[Spread from High Temp End]
    C --> D[Dry Coat Thickness 0.10-0.15 mm]
    D --> E[Observe Film Formation]
    E --> F{Continuous Film?}
    F -- Yes --> G[Record MFT]
    F -- No --> H[Increase Temp and Repeat]

Note: Use a calibrated temperature-controlled plate for accurate MFT and WP determination.

IS 13435 Part 5: Devices for Temperature Measurement

Key Specifications:

• Temperature Range: -10°C to +15°C
• Accuracy: ±0.1°C
• Devices Used:
  • Mercury thermometers
  • Resistance thermometers (RTDs)
  • Thermocouples
  • Semiconductor probes

Setup & Measurement:

• Thermometer holes of 0.5 mm diameter are evenly spaced along the plate surface to measure temperature gradients (Clause 4.1.3).
• The first hole is at the cold end, perpendicular to the start of the channel if present.
• Temperature readings are recorded at these points once equilibrium is reached (Clause 5.1.1).

Data Analysis:

• Plot temperature (ordinate) vs. distance between devices (abscissa) (Clause 5.2.6).
• If the temperature gradient is linear, the plot is a straight line, and graphing may be omitted.

Typical Arrangement (from FIG.1):

Formula for Temperature Gradient (if needed):

[ \frac{dT}{dx} = \frac{T_2 - T_1}{x_2 - x_1} ]

Where:

• (T_1, T_2) = temperatures at two adjacent points
• (x_1, x_2) = corresponding distances along the plate

graph LR
A[Cold End Thermometer Hole] --> B[Intermediate Holes]
B --> C[Hot End Thermometer Hole]
C --> D[Temperature Gradient Plot]

This setup ensures accurate measurement of temperature distribution on the plate surface as per IS 13435 Part 5.

IS 13435 Part 5: Film Spreader Key Points

Film Spreader Specifications (Clause 4.3)

• Material: Stainless steel.
• Capable of producing:
  • Films in channels.
  • Films ~0.1 mm thick and 20–25 mm wide as plates without channels.

Film Thickness & Width (Clauses 5.2.1 & 5.2.2)

• Dry coat thickness: 0.10 to 0.15 mm.
• Width of coat: 20 mm.
• Spreading starts from the end with the highest temperature.
• For channelled plates, pour into the channel and spread similarly.

Minimum Film Forming Temperature (MFT) & White Point (WP) (Clause 5.2.8)

• MFT: Lowest temperature where a continuous, homogeneous film forms.
• WP: White point temperature where the film starts to whiten.
• Both to be determined to the nearest °C.

Reporting Requirements (Clause 6)

• Identification of dispersion.
• Type of testing apparatus.
• White point temperature (°C).
• Minimum film forming temperature (°C).

Summary Table: Film Spreader Parameters

flowchart LR
    A[Start at highest temperature end] --> B[Pour dispersion]
    B --> C{Channelled plate?}
    C -- Yes --> D[Pour into channel]
    C -- No --> E[Spread film plate]
    D --> F[Use film spreader to spread]
    E --> F
    F --> G[Dry coat thickness 0.10-0.15 mm]
    G --> H[Width 20-25 mm]
    H --> I[Measure MFT & WP temperatures]

For precise test setup and film spreader design, refer to Fig. 2 of IS 13435 Part 5.

IS 13435 Part 5 covers the determination of Minimum Film Forming Temperature (MFFT) and White Point for acrylic-based polymer aqueous dispersions used in waterproofing.

Key Concepts:

• Minimum Film Forming Temperature (MFFT): Lowest temperature at which a polymer dispersion forms a continuous film upon drying.
• White Point: Temperature at which the dried film shows visible whiteness or opacity, indicating incomplete coalescence.

Typical Procedure Summary:

• Apply polymer dispersion on a substrate.
• Dry at varying temperatures.
• Observe film formation and whiteness visually or using instruments.

Important Specifications:

• MFFT is critical for ensuring proper film formation under service conditions.
• White point indicates the temperature below which film quality deteriorates.

Common Formula (empirical):

No direct formula in IS 13435 Part 5, but MFFT often correlates with polymer Tg (glass transition temperature):

[ \text{MFFT} \approx \text{Tg} - 10^\circ C ]

Typical Table (illustrative):

flowchart LR
    A[Polymer Dispersion] --> B[Apply on Substrate]
    B --> C{Dry at Temp T}
    C -->|T > MFFT| D[Clear Film]
    C -->|T ≈ White Point| E[Partial Coalescence]
    C -->|T < White Point| F[White, Opaque Film]

Summary: IS 13435 Part 5 provides a standardized method to identify MFFT and White Point, ensuring polymer films perform well in waterproofing applications.

IS 13435 Part 5: Setting the Temperature Gradient

Key Specifications:

• Temperature Gradient Linearity (Clause 5.1.3):
  The temperature gradient along the plate must be linear. This means:

  • Equal distances along the plate correspond to equal temperature drops.
  • Pressure drop across each segment is equal.

• Temperature Measurement (Clause 4.1.3 & 5.2.6):

  • Thermometer holes are evenly spaced along the plate length, starting at the cold end, perpendicular to the channel start.
  • Record temperatures at these points after equilibrium.
  • Plot temperature (ordinate) vs. distance (abscissa).
  • If the plot is a straight line, the gradient is linear, and graphing may be omitted.

Practical Approach:

Formula:

[ \text{Temperature Gradient} = \frac{T_{i} - T_{i+1}}{d} ]

where (T_i) and (T_{i+1}) are temperatures at consecutive points, and (d) is distance between them.

graph LR
A[Cold End] -->|d| B[Point 1: T1]
B -->|d| C[Point 2: T2]
C -->|d| D[Point 3: T3]
D -->|d| E[Hot End: Tn]

subgraph Temperature Gradient
    T1 --> T2 --> T3 --> Tn
end

Summary: Use evenly spaced temperature points, verify linear temperature drop (equal ΔT per equal d), ensuring a linear temperature gradient per IS 13435 Part 5.

IS 13435 Part 5: Procedure for MFT and WP Determination

Key Points from Clause 5.2 & 5.2.8

• Minimum Film Forming Temperature (MFT):
  The lowest temperature at which a continuous, homogeneous film without defects forms on the substrate.

  • Determined to the nearest 1°C.

• White Point (WP):
  The temperature at which the film starts to whiten or shows opacity due to incomplete coalescence.

Procedure Summary

1. Sample Preparation:
   Use a film spreader (see FIG. 2 in the standard) to apply the dispersion uniformly on a channeled plate.

2. Temperature Variation:
   Gradually cool or heat the sample and observe the film appearance.

3. Observation:

   • Identify the temperature where film first forms continuously (MFT).
   • Note the temperature where whitening appears (WP).

Reporting Requirements (Clause 6)

• Dispersion identification
• Testing apparatus type
• White Point temperature (°C)
• Minimum Film Forming Temperature (°C)

Table: Typical MFT and WP Values (Example)

Visual Concept: Film Formation vs Temperature

graph LR
A[High Temp: Continuous Film] --> B[MFT: Film forms]
B --> C[WP: Whitening begins]
C --> D[Low Temp: Film breaks/whitens]

This procedure ensures consistent quality control for coatings by defining the critical temperature parameters for film formation and appearance.

IS 13435 Part 5 – Reporting of the Result: Key Points

1. Rounding Off Values

   • Follow IS 2:1960 for rounding numerical values in test results.

2. Test Report Must Include:

   • Identification of the dispersion tested
   • Type of testing apparatus used
   • White Point Temperature (WP) in °C
   • Minimum Film Forming Temperature (MFT) in °C (nearest degree Celsius)

3. Definitions:

   • MFT: Lowest temperature at which a continuous homogeneous film forms without gaps.
   • WP: Temperature at which the dispersion shows a white point (specific to the test).

4. Table 5.2 (Clause 5.2.8) Summary:

   • Used for determination of MFT and WP (details in the standard).
   • MFT is recorded to the nearest °C.

Reporting Format Example

Additional Notes

• Use the Standard Mark only as per BIS rules.
• Ensure all results comply with the latest version of IS 13435 and amendments.

flowchart TD
    A[Test Conducted] --> B{Record Values}
    B --> C[White Point Temperature (°C)]
    B --> D[Minimum Film Forming Temperature (°C)]
    C --> E[Round off per IS 2:1960]
    D --> E
    E --> F[Prepare Test Report]
    F --> G[Include Identification & Apparatus]
    F --> H[Include WP & MFT values]

This ensures standardized, clear, and accurate reporting of dispersion test results per IS 13435 Part 5.